JP4670072B2 - Lubricating oil composition in contact with lead-containing metal material - Google Patents

Description

  The present invention relates to a lubricating oil composition in contact with a lead-containing metal material, and in particular, a lubricating oil composition capable of suppressing corrosion or corrosive wear of a lead-containing sliding material even when the content of zinc dithiophosphate is small. In particular, the present invention relates to a lubricating oil composition that can suppress corrosion or corrosive wear of a lead-containing sliding material even when a salicylate detergent is used.

  Iron-based materials are mainly used for sliding materials such as engines, but lead-containing metals are sometimes used for sliding parts such as main bearings and connecting rod bearings, such as bearing metals. These lead-containing metals have an excellent feature that there is little fatigue phenomenon, but on the other hand, there is a drawback that the corrosion wear is large.

  Causes of such corrosion include accumulation of peroxides due to oil degradation (for example, Non-Patent Document 1) and direct oxidation with molecular oxygen in the air (for example, Non-Patent Documents 2 to 4), quinone, It is known that oxidation products such as diacetyl, nitric oxide, and nitro compounds also promote corrosion when coexisting with an acid (for example, Non-Patent Document 5).

Actual corrosion is complex because it is governed by many of these factors, but in general,
・ Anti-oxidation of lubricating oil ・ Destruction of oxidizing substances ・ Suppression of formation of corrosive oxidation products ・ Deactivation of acidic substances ・ Formation of anti-corrosion coating on metal surfaces are important.

More specifically,
・ Peroxide decomposing agents such as zinc dithiophosphate and sulfides and anticorrosion film forming agents ・ Amine-based and phenol-based chain-stopping antioxidants ・ Anti-corrosion film forming agents such as benzotriazole ・ Cleaning dispersant The effect of preventing corrosion due to the addition of an acid neutralizer is known, and most of the above four components are generally used in combination. In particular, sulfur-containing wear inhibitors such as zinc dithiophosphate are extremely effective for preventing corrosion and wear of lead-containing sliding materials. For example, zinc dithiophosphate is about 0.1% in terms of phosphorus (sulfur content). In conventional engine oils blended in excess of about 0.2% by mass), the lead surface abrasion is inactivated by the peroxide decomposition and the lead corrosion wear prevention effect is excellent, but it contains zinc dithiophosphate. When the amount is reduced, it is known that the corrosion wear prevention effect of lead deteriorates exponentially (see, for example, Non-Patent Document 6). On the other hand, sulfur-containing compounds such as zinc dithiophosphate are prone to sulfide corrosion on lead-containing metal-containing sliding materials other than lead (for example, copper, tin, silver, etc.), and corrosion inhibitors such as benzotriazole are It has been found that it is effective in preventing copper corrosion, but does not show sufficient effect in preventing lead corrosion.

  By the way, against the backdrop of recent demands for reducing environmental impact, there is a growing demand for low phosphorus or low sulfur as well as long life of engine oil. The long life of engine oil is the fuel in gasoline engines and diesel engine engines. Suppression of engine oil deterioration caused by fuel, such as reduction of sulfur content in gas, and widespread use of gas-fueled engine engines, higher performance of engine oil itself (increased antioxidant, wear inhibitor, metal detergent and other additives, etc.) ) To achieve a long life in terms of base number maintenance (see, for example, Patent Document 1). Further, it has been found that a longer life can be achieved by using a salicylate detergent having a lower metal ratio (for example, Patent Documents 2 to 4).

Also, in diesel engine engines, the amount of sulfated ash in the engine oil is reduced in order to suppress deposits on exhaust purification devices such as DPF, and in gas engine engines, to suppress deposits in the combustion chamber that cause abnormal combustion. The demand for reduction is high, and when reducing metal-based detergents, it is considered that the use of salicylate-type detergents is most preferable from the viewpoint of maintaining the base number.
Ind.Eng.Chem., 36 (1944), 477 ibid., 37 (1945), 90 ibid., 49 (1957), 1703 J. Inst. Petrol., 37 (1951), 225 Ind.Eng.Chem., 37 (1945), 917 Edited by Toshio Sakurai, Petroleum Product Additives, Second Edition, page 271 Figure-8 (issued June 15, 1979, Kobo Shobo) JP 2002-294271 A JP 2003-277781 A Japanese Patent Laid-Open No. 2003-277782 JP 2003-277783 A

  The inventors of the present invention have reduced the zinc dithiophosphate or reduced and / or reduced sulfur-free engine oils, particularly salicylate detergents that are excellent in oxidation stability and most effective in maintaining base number. As a result of examining wear prevention performance for various sliding materials (iron-based, aluminum-based, copper-based, lead-based, etc.) when used for a longer period of time than before, the total base number of lubricating oil remains sufficiently However, it has been found that the corrosion wear of the lead-containing sliding material may occur remarkably even though it has not reached the end of its life. In particular, lead corrosion is significant in an oxidizing gas atmosphere, so that the degradation of peroxide and the formation of anticorrosion coating on lead can be reduced by reducing, not using, or disappearing zinc dithiophosphate after long-term use. Along with disappearance, it is thought that the degradation products of the lubricating oil act on the lead surface and accelerate lead corrosion. This lead corrosion phenomenon occurs despite the fact that the salicylate-based detergent remains sufficiently and has acid neutralizing ability and antioxidant performance, so that the zinc dithiophosphate that has been conventionally used is reduced or reduced. It can be said that this is a new problem that has become apparent when it is not contained.

  That is, the object of the present invention is to optimize the additive composition in a lubricating oil composition that significantly reduces the corrosion of lead-containing metals such as lead-containing sliding materials that reduce or do not contain zinc dithiophosphate. Providing a lubricating oil composition that can suppress lead corrosion that occurs even when the base number remains, or a method for preventing corrosion or corrosive wear of lead-containing sliding materials by using such a lubricating oil composition It is to be.

  As a result of intensive studies to solve the above problems, the present inventors have optimized an ashless dispersant even when zinc dithiophosphate is reduced or not contained, particularly when a salicylate-based detergent is contained. As a result, it was found that corrosion or corrosive wear of the lead-containing metal material can be suppressed, and the present invention has been completed.

  That is, in the present invention, the lubricant base oil does not contain 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount, and 0.01 to 0.4% by mass of a succinimide-based ashless dispersant as a nitrogen amount. A succinimide-based ashless dispersant comprising (A) a bis-type succinimide having a weight average molecular weight of 5000 or more and / or The lubricating oil composition is characterized in that the derivative contains a nitrogen ratio (mass ratio) of 0.5 or more.

  In this specification, “weight average molecular weight” means that two columns of Tosoh GMHHR-M (7.8 mm ID × 30 cm) are used in series on a Waters 150-C ALC / GPC apparatus, and the solvent is Tetrahydrofuran, temperature 23 ° C., flow rate 1 mL / min, sample concentration 1% by mass, sample injection amount 75 μL, weight average molecular weight in terms of polystyrene measured with a detector differential refractometer (RI).

  Further, in the present invention, the lubricant base oil contains 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount or 0.01 to 0.4% by mass of a succinimide ashless dispersant as a nitrogen amount. A lubricating oil composition in contact with a lead-containing metallic material, further comprising a salicylate-based detergent, wherein the succinimide-based ashless dispersant is (A) a bismuth having a weight average molecular weight of 5000 or more. The lubricating oil composition according to the present invention contains a succinimide of a type and / or a derivative thereof in a nitrogen ratio (mass ratio) of 0.5 or more.

  The component (A) is a boron compound derivative of a bis-type succinimide having a weight average molecular weight of 5000 or more, and its content is 0.01% by mass or more as a boron amount based on the total amount of the composition. Preferably there is.

  The lubricating oil composition contains one or more selected from phosphorus additives other than zinc dithiophosphate, ashless antioxidants, corrosion inhibitors, and viscosity index improvers. preferable.

  In the present invention, the lead-containing metal material preferably contains 1 to 100% by mass of lead.

  Moreover, it is preferable that the said composition is for diesel engines or gas engines.

  Further, in the present invention, the lubricant base oil contains 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount or 0.01 to 0.4% by mass of a succinimide ashless dispersant as a nitrogen amount. A method for preventing corrosion or corrosive wear of lead-containing metal materials in contact with a contained lubricating oil composition, wherein the succinimide-based ashless dispersant is (A) a bis-type succinic acid having a weight average molecular weight of 5000 or more. Corrosion or corrosion wear prevention of lead-containing metal materials characterized by using a succinimide-based ashless dispersant containing imide and / or a derivative thereof in a nitrogen ratio (mass ratio) of 0.5 or more Is in the way.

  The lubricating oil composition in contact with the lead-containing metal material of the present invention has a lead (Pb) content especially when zinc dithiophosphate, which is extremely effective in preventing corrosion or corrosion wear of lead (Pb), is reduced or not contained. It is a lubricating oil composition that can suppress corrosion or corrosive wear, and can be reduced in sulfur, further reduced in phosphorus, reduced in ash, and has excellent long drainage properties. Accordingly, not only as a lubricating oil for internal combustion engines in contact with a lead-containing metal material, particularly as diesel engine oil or gas engine oil with a lead-based sliding material, but also a device having a lubrication system in which the lead-containing metal material and the lubricant come into contact Lubricating oils, for example, automatic transmissions, manual transmissions, continuously variable transmissions, gear system lubricating oils, greases, wet brake oils, hydraulic fluids, turbine oils, compressor oils, bearing oils, refrigeration machine oils, etc. It can also be suitably used as a lubricating oil.

  The lubricating oil composition in contact with the lead-containing metal material of the present invention has a zinc dithiophosphate content of 0.08% by mass or less as a phosphorus amount or does not contain this, and a lead-containing metal that becomes prominent in that case It is a lubricating oil composition for preventing corrosion or corrosive wear of a material, and is a composition in which an ashless dispersant is optimized.

  In addition, the lubricating oil composition in contact with the lead-containing metal material of the present invention is a salicylate-based cleanser having a zinc dithiophosphate content of 0.08% by mass or less as a phosphorus amount or not containing it and having excellent base number maintenance performance. It is a lubricating oil composition for preventing corrosion or corrosive wear of a lead-containing metal material that becomes particularly prominent when it contains an agent, and is a composition in which an ashless dispersant is optimized. Hereinafter, a lubricating oil composition (also simply referred to as a lubricating oil composition or a composition) in contact with the lead-containing metal material of the present invention will be described in detail.

  In the present invention, the lead-containing metal material is not limited as long as lead is present on the metal surface in contact with the lubricating oil of the present invention. Not only lead, but also lead alloys, lead or lead alloys can be selected from various metals. Examples thereof include a metal material coated on the surface of the substrate. Moreover, even if the lead-containing metal material is coated with a non-lead-containing metal material on its surface, the coated surface is worn away in the process of use, and the lead-containing metal material is exposed, and is in contact with the lubricating oil of the present invention. This includes cases where there is a possibility of doing so.

  Examples of lead alloys include lead-tin alloys, lead-copper alloys, lead-tin-copper alloys, lead-aluminum alloys, lead-aluminum-silicon alloys, lead-aluminum-tin alloys, lead-aluminum-copper alloys, Lead-aluminum-silicon-tin alloy, lead-aluminum-silicon-copper alloy, lead-aluminum-tin-copper alloy, lead-aluminum-silicon-tin-copper alloy, and the like. As these lead-containing metal materials, It is preferable that the metal material contains a lead content of preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 5% by mass or more, and further preferably 10% by mass or more. Specifically, a lead-tin-containing alloy containing 50 to 95 mass%, preferably 60 to 90 mass% of lead, and a lead-copper-containing alloy containing 5 to 50 mass%, preferably 10 to 30 mass% of lead. And a lead-aluminum-containing alloy containing 1 to 10% by mass, preferably 2 to 5% by mass of lead.

  The lubricating oil composition of the present invention is useful because the higher the lead content on the metal surface, the more likely lead corrosion or corrosion wear occurs.

  The lubricating base oil in the present invention is not particularly limited, and mineral oil base oils and synthetic base oils used for ordinary lubricating oils can be used. Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Examples include those refined by performing one or more treatments such as solvent dewaxing, hydrorefining, etc., or base oils produced by a method of isomerizing wax isomerized mineral oil, GTL WAX (Gas Liquid Wax).

  The sulfur content in the mineral oil base oil is not particularly limited, but is usually 0 to 0.8% by mass, preferably 0.6% by mass or less, more preferably 0.5% by mass or less, and further preferably. Is 0.4 mass% or less, particularly preferably 0.3 mass% or less, preferably 0.05 mass% or more, more preferably 0.1 mass% or more. When it is used as a lubricating oil for an internal combustion engine, the sulfur content is 0.2% by mass or less, preferably 0.1% by mass or less, more preferably 0.05% by mass or less. A low-sulfur lubricating oil composition that can avoid adverse effects on the exhaust gas aftertreatment device as much as possible can be obtained.

  The saturated content of the mineral oil base oil is not particularly limited, but is usually 50 to 100% by mass, preferably 60% by mass or more, and more preferably 70% by mass in terms of excellent oxidation stability and long drainability. % Or more, more preferably 80% by mass or more, and preferably 98% by mass or less, more preferably 95% by mass or less, and particularly preferably 90% by mass or less from the viewpoint of the solubility of the additive and sludge solubility. .

  In addition, the said saturated part means the saturated part measured based on ASTM D2549.

  Specific examples of synthetic base oils include polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate Diesters such as diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; neopentyl glycol ester, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol Examples thereof include polyol esters such as pelargonate; aromatic synthetic oils such as alkyl naphthalene, alkyl benzene, and aromatic esters, or mixtures thereof.

  As the lubricating base oil in the present invention, the above mineral base oil, the above synthetic base oil, or an arbitrary mixture of two or more selected from these can be used. Examples thereof include one or more mineral base oils, one or more synthetic base oils, a mixed oil of one or more mineral base oils and one or more synthetic base oils, and the like.

The kinematic viscosity of the lubricating base oil used in the present invention is not particularly limited, but the kinematic viscosity at 100 ° C. is preferably 20 mm ² / s or less, more preferably 16 mm ² / s or less. On the other hand, the kinematic viscosity is preferably 3 mm ² / s or more, more preferably 5 mm ² / s or more, and still more preferably 8 mm ² / s or more. When the kinematic viscosity at 100 ° C. of the lubricating base oil exceeds 20 mm ² / s, the low-temperature viscosity characteristic deteriorates. On the other hand, when the kinematic viscosity is less than 3 mm ² / s, an oil film is formed at the lubrication point. Insufficient lubrication results in poor lubricity and increases the evaporation loss of the lubricating base oil, which is not preferable.

  The amount of evaporation loss of the lubricating base oil is preferably 20% by mass or less, more preferably 16% by mass or less, further preferably 10% by mass or less, and 6% by mass in terms of NOACK evaporation. % Or less is more preferable, and 5% by mass or less is particularly preferable. When the NOACK evaporation amount of the lubricating base oil exceeds 20% by mass, not only the evaporation loss of the lubricating oil is large and the long drain property is inferior, but also when used as a lubricating oil for an internal combustion engine, Phosphorus compounds or metal components may accumulate in the exhaust gas purification device together with the lubricating base oil, which is not preferable because there is a concern about adverse effects on the exhaust gas purification performance. Here, the NOACK evaporation amount is measured in accordance with ASTM D5800.

  The viscosity index of the lubricating base oil is not particularly limited, but the value is preferably 80 or more, more preferably 100 or more, and still more preferably so that excellent viscosity characteristics can be obtained from low temperature to high temperature. 120 or more. There is no particular limitation on the upper limit of the viscosity index, normal paraffin, slack wax, GTL wax and the like, or those of about 135 to 180 such as isoparaffin mineral oil obtained by isomerizing these, complex ester base oil, HVI-PAO system The thing of about 150-250 like base oil can also be used. When the viscosity index of the lubricating base oil is less than 80, the low temperature viscosity characteristics deteriorate, which is not preferable.

  Examples of the zinc dithiophosphate in the present invention include those represented by the following general formula (1) as zinc dithiophosphate.

In the formula, R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and these hydrocarbon groups having 1 to 24 carbon atoms include those having 1 to 24 carbon atoms. A linear or branched alkyl group, a linear or branched alkenyl group having 3 to 24 carbon atoms, a cycloalkyl group having 5 to 13 carbon atoms, or a linear or branched alkylcycloalkyl group, It is preferably any of an aryl group having 6 to 18 carbon atoms, a linear or branched alkylaryl group, an arylalkyl group having 7 to 19 carbon atoms, and the like. The alkyl group or alkenyl group may be primary, secondary or tertiary.

Among the hydrocarbon groups which R ¹ , R ² , R ³ and R ⁴ can take, the hydrocarbon group is a linear or branched alkyl group having 1 to 18 carbon atoms, or 6 carbon atoms. Particularly preferred is an aryl group of ˜18 or a linear or branched alkylaryl group.

Any conventional method can be adopted as a method for producing zinc dithiophosphate and is not particularly limited. Specifically, for example, it has a hydrocarbon group corresponding to R ¹ , R ² , R ³ and R ^4. It can be synthesized by reacting alcohol or phenol with diphosphorus pentasulfide to produce dithiophosphoric acid and neutralizing it with zinc oxide. The structure of zinc dithiophosphate varies depending on the starting alcohol used.

  The upper limit of the content of zinc dithiophosphate in the lubricating oil composition of the present invention is 0.08% by mass or less, preferably 0.05% by mass or less, particularly preferably 0.04% by mass or less, as the amount of phosphorus. The lower limit is not particularly limited, and it is desirable not to contain this from the viewpoint of maintaining the base number, but it can be included if necessary to improve the corrosion or corrosion wear prevention performance of the lead-containing metal material. The content of phosphorus is preferably 0.01% by mass or more, more preferably 0.02% by mass.

  When the content of zinc dithiophosphate exceeds 0.08% by mass as the amount of phosphorus, for example, when the amount of phosphorus is 0.10% by mass or more, the conventional lubricating oil deviates from the conditions in which the problem of the present invention becomes significant. Yes, although the lead-containing metal material is excellent in corrosion or corrosion wear prevention performance, it is not preferable from the viewpoint of low sulfur, low phosphorus, or long life.

  The lubricating oil composition of the present invention contains a succinimide-based ashless dispersant in an amount of 0.01 to 0.4% by mass as a nitrogen amount based on the total amount of the composition.

  As the succinimide-based ashless dispersant, any succinimide-based ashless dispersant used in lubricating oils can be used. For example, a linear or branched alkyl group or alkenyl having 40 to 400 carbon atoms. Examples thereof include succinimide having at least one group in the molecule and / or a derivative thereof. The alkyl group or alkenyl group has 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms. When the carbon number of the alkyl group or alkenyl group is less than 40, the solubility of the compound in the lubricating base oil decreases. On the other hand, when the carbon number of the alkyl group or alkenyl group exceeds 400, the low temperature of the lubricating oil composition Since fluidity | liquidity deteriorates, it is unpreferable respectively. This alkyl group or alkenyl group may be linear or branched, but specifically, preferred are derived from olefin oligomers such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene. And a branched alkyl group and a branched alkenyl group.

  More specifically, examples of the succinimide include compounds represented by the following general formula (2) and general formula (3).

In the general formula (2), R ⁵ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and h represents an integer of 1 to 5, preferably 2 to 4.

In the general formula (3), R ⁶ and R ⁷ each independently represent an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and is preferably a polybutenyl group. i represents an integer of 0 to 4, preferably 1 to 3.

  The succinimide includes a so-called monotype succinimide represented by the general formula (2) in which succinic anhydride is added to one end of the polyamine, and a general formula in which succinic anhydride is added to both ends of the polyamine ( The so-called bis-type succinimide represented by 3) is included, and the composition of the present invention may include any of them or a mixture thereof.

  The method for producing these succinimides is not particularly limited. For example, an alkyl or alkenyl succinic acid obtained by reacting a compound having an alkyl group or alkenyl group having 40 to 400 carbon atoms with maleic anhydride at 100 to 200 ° C. It can be obtained by reacting with a polyamine. Specific examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

  Examples of the succinimide derivatives include boron compounds such as boric acid and borates, phosphorus compounds such as (thio) phosphoric acid and (thio) phosphate, and carboxylic acids having 1 to 30 carbon atoms. And the like, and derivatives obtained by acting an organic acid such as hydroxy (poly) oxyalkylene carbonate. In the present invention, one or two or more arbitrarily selected from these can be blended.

  The content of the succinimide-based ashless dispersant in the present invention is 0.01% by mass or more, preferably 0.05% by mass or more, and 0.4% by mass or less as the nitrogen content based on the total amount of the composition. Preferably it is 0.1 mass% or less, Most preferably, it is 0.08 mass% or less. When the content of succinimide-based ashless dispersant is less than 0.01% by mass as nitrogen content, the cleanliness and sludge dispersibility are inferior. When the content exceeds 0.4% by mass, not only the low-temperature fluidity is deteriorated. Lead corrosion gets worse.

  In the lubricating oil composition of the present invention, as the succinimide-based ashless dispersant, (A) a bis-type succinimide having a weight average molecular weight of 5000 or more and / or a derivative thereof must be contained as an essential component. The weight average molecular weight is preferably 5500 or more, more preferably 5800 or more, and preferably has a low temperature fluidity of preferably 20000 or less, more preferably 15000 or less, still more preferably 10,000 or less, particularly preferably. 6500 or less or less. Further, the content is 0.5 or more, preferably 0.7 or more, particularly preferably 0.9 or more and 1.0 or less in terms of nitrogen ratio (mass ratio) with respect to the total amount of succinimide ashless dispersant. is there. Even if it contains the component (A), it contains other succinimides, for example, bis-type succinimides having a weight average molecular weight of less than 5000 or mono-type succinimides, and the nitrogen ratio is This is because it is difficult to obtain the effects of the present invention when it is less than 0.5. When producing a bis-type succinimide, a mono-type succinimide may be contained as a by-product or an impurity, but the bis-type succinimide in the present invention includes such a succinimide. Also included. Even in such a case, the nitrogen ratio (mass ratio) of the monotype succinimide content to the total amount of the succinimide-based ashless dispersant in the lubricating oil composition of the present invention is 0.4 or less. It is preferable to adjust so that it may be, More preferably, it is 0.2 or less, Most preferably, it is 0.1 or less.

  Here, the “weight average molecular weight” of the succinimide-based ashless dispersant is obtained by using two columns of Tosoh GMHR-M (7.8 mm ID × 30 cm) in series on a Waters 150-C ALC / GPC apparatus. The solvent means tetrahydrofuran, a temperature of 23 ° C., a flow rate of 1 mL / min, a sample concentration of 1 mass%, a sample injection amount of 75 μL, and a polystyrene-reduced weight average molecular weight measured with a detector differential refractometer (RI).

  In the present invention, the component (A) is a poly (iso) butenyl succinimide obtained by modifying a bis-type succinimide having a weight average molecular weight of 5000 or more with a boron compound such as boric acid or borate. Most preferred is a boron compound derivative, and the mass ratio (B / N) of boron and nitrogen in the boron compound derivative is not particularly limited, but is preferably 0.1 or more, more preferably 0.2 or more. Yes, preferably 2 or less, more preferably 0.8 or less, particularly preferably 0.6 or less, particularly preferably 0.4 or less. In addition, the boron compound derivative content is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and particularly preferably 0 as the boron content based on the total amount of the composition. 0.02% by mass or more, and if the content of the boron compound derivative increases, there is a concern about the influence on the sealing material and an increase in sulfated ash content. Therefore, the content is preferably 0.2% by mass as the boron content. Or less, more preferably 0.1% by mass or less, further preferably 0.08% by mass or less, further preferably 0.06% by mass or less, further preferably 0.04% by mass or less, and particularly preferably 0.03% by mass. Less than or less than mass%.

  The lubricating oil composition of the present invention preferably contains a metallic detergent. Examples of metal detergents include sulfonate detergents, finate detergents, salicylate detergents, and the like.

  More specifically, the sulfonate detergent is a metal salt of an alkyl aromatic sulfonic acid obtained by sulfonated an alkyl aromatic compound having a molecular weight of 100 to 1500, preferably 200 to 700, preferably an alkaline earth. Metal salts, particularly magnesium salts and / or calcium salts are preferably used, and specific examples of alkyl aromatic sulfonic acids include so-called petroleum sulfonic acids and synthetic sulfonic acids.

  As the petroleum sulfonic acid, there are generally used those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil, so-called mahoganic acid that is produced as a by-product when white oil is produced. As the synthetic sulfonic acid, for example, an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant that is a raw material for detergents or by alkylating polyolefin into benzene, is used as a raw material. And those obtained by sulfonating this, or those obtained by sulfonating dinonylnaphthalene. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but usually fuming sulfuric acid or sulfuric acid is used.

  Examples of the alkaline earth metal sulfonate include those represented by the following general formula (4) or (5).

In the formula, R ⁸ and R ⁹ may be the same or different and each represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 8 to 25, and M ¹ is an alkaline earth metal, preferably Represents calcium and / or magnesium.

  More specifically, the finate-based detergent is an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and reacting this alkylphenol with elemental sulfur. A metal salt, preferably an alkaline earth metal salt, particularly a magnesium salt and / or a calcium salt of an alkylphenol sulfide product obtained by reacting the alkylphenol obtained by reacting the alkylphenol with formaldehyde is preferable.

  Examples of the alkaline earth metal finate include those represented by the following general formulas (6) to (8).

In the formula, R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ may be the same or different, and each represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. M ² , M ³ and M ⁴ are each an alkaline earth metal, preferably calcium and / or magnesium, and x is an integer of 1 to 2.

  More specifically, the salicylate-based detergent is a metal of alkyl salicylic acid having at least one linear or branched alkyl group having 4 to 32 carbon atoms, preferably 6 to 19 carbon atoms or 20 to 30 carbon atoms. Salts, preferably alkaline earth metal salts, particularly magnesium salts and / or calcium salts are preferably used.

  Examples of the alkaline earth metal salicylate include those represented by the following general formula (9).

In the formula, R ¹⁶ and R ¹⁷ may be the same or different and each represents hydrogen or a linear or branched alkyl group having 1 to 32 carbon atoms, and at least one of them is 8 to 32 carbon atoms, preferably 14 ˜32 linear or branched alkyl groups, M ⁵ represents an alkaline earth metal, preferably calcium and / or magnesium. As the alkaline earth metal salicylate of the present invention, one of R ¹⁶ and R ¹⁷ is derived from hydrogen, and the other is derived from a linear α-olefin having 14 to 32 carbon atoms, preferably 14 to 19 carbon atoms or 20 to 30 carbon atoms. When alkaline earth metal salicylates that are secondary alkyl groups are used, lead corrosion or corrosive wear is likely to occur, and therefore a composition satisfying the other constitution of the present invention that can suppress this is particularly useful. It is. In the present invention, an alkaline earth metal salicylate which is a secondary alkyl group derived from a linear α-olefin having 20 to 30 carbon atoms is most preferable in that lead corrosion or corrosion wear can be further suppressed.

  Alkali earth metal sulfonate detergents, alkaline earth metal finate detergents and alkaline earth metal salicylate detergents include alkyl aromatic sulfonic acids, alkylphenols, alkylphenol sulfides, Mannich reaction products of alkylphenols, alkyl Salicylic acid or the like is directly reacted with an alkaline earth metal base such as magnesium and / or calcium alkaline earth metal oxide or hydroxide, or once converted to an alkali metal salt such as sodium salt or potassium salt and then alkalinized. Not only neutral salts (normal salts) obtained by substituting with earth metal salts, but also neutral salts (normal salts) and excess alkaline earth metal salts or alkaline earth metal bases (alkaline) Earth metal hydroxides and oxides) in the presence of water The obtained basic salt or excess obtained by reacting a neutral salt (normal salt) with a base such as an alkali metal or alkaline earth metal hydroxide in the presence of carbon dioxide gas, boric acid or borate. Also included are basic salts (superbasic salts).

  These reactions are usually carried out in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricating base oil). In addition, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are available, but generally the metal content is 1.0 to 20% by mass. It is desirable to use 2.0 to 16% by mass.

  These metal detergents are preferably selected to have a specific soap ratio. For example, the soap ratio is 0.6 or more, preferably 0.7 or more, 1 or less, preferably 0.9. Hereinafter, it is more preferable to contain a sulfonate detergent (a) of 0.85 or less. For example, it is further desirable to include an overbased metal detergent (b) having a soap ratio of less than 0.6, preferably 0.4 or less, particularly 0.2 or less. From the viewpoint of stability and the like, it is desirable to set it to 0.01 or more, preferably 0.05 or more. As these overbased metal detergents, it is preferable to use one or more selected from overbased sulfonates, overbased finates, and overbased salicylates, and overbased sulfonates and / or overbased sulfonates. It is preferred to use basic salicylates, and it is particularly desirable to use overbased sulfonates.

  In the lubricating oil composition of the present invention, the content of zinc dithiophosphate is 0.08% by mass or less as the amount of phosphorus, and among the above-mentioned metal detergents, salicylate detergents, particularly soap ratio is 0.6 or more, In particular, when the salicylate-based detergent (c) of 0.7 or more and 1 or less is contained as an essential component, lead corrosion or corrosion wear is accelerated, so the soap ratio is less than 1, preferably 0.9 or less, more preferably Is preferably 0.85 or less, and optimization of the succinimide-based ashless dispersant of the present invention as described above is particularly important.

  Here, the soap ratio means the ratio (mass ratio) of the amount of metal caused by soap (equivalent metal salt) to the total amount of metal contained in each metal detergent, and the soap is, for example, the above general formula Equivalent metal salts such as alkaline earth metal sulfonates, alkaline earth metal finates, alkaline earth metal salicylates represented by (4) to (9), and overbasing components such as calcium carbonate and calcium borate It is not included. In addition, the total amount of metal contained in the metal detergent includes all the metals contained in the metal detergent, such as the amount of metal resulting from the soap, the amount of metal resulting from overbasing components such as calcium carbonate and calcium borate. The total amount of metal. Specifically, the soap ratio is the ratio (mass ratio) of the metal amount derived from the sulfonate soap (equivalent metal salt) to the total metal amount in the sulfonate detergent, and the salicylate soap relative to the total metal amount in the salicylate detergent. This means the ratio (mass ratio) of the amount of metal due to (equivalent metal salt), the ratio (mass ratio) of the amount of metal due to finate soap (equivalent metal salt), etc. with respect to the total amount of metal in the finate detergent. .

  In the lubricating oil composition of the present invention, when the sulfonate detergent (a) having a soap ratio of 0.6 or more is contained, the content is not particularly limited, but usually the metal amount based on the total amount of the lubricating oil composition 0.01 mass% or more, preferably 0.05 mass% or more, more preferably 0.1 mass% or more, and from the viewpoint of reducing sulfated ash content of the composition, preferably 0.5 mass% or less, more Preferably it is 0.3 mass% or less, More preferably, it is 0.2 mass% or less.

  Further, in the lubricating oil composition of the present invention, when the overbased metal detergent (b) having a soap ratio of less than 0.6 is contained, the content is not particularly limited, but usually the total amount of the lubricating oil composition Based on the standard, the metal amount is 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and preferably 5% by mass or less. From the viewpoint of reduction, it is 0.5% by mass or less, preferably 0.3% by mass or less, more preferably 0.2% by mass or less.

  In the lubricating oil composition of the present invention, when the salicylate detergent (c) having a soap ratio of 0.6 or more is contained, the content is not particularly limited, but usually the metal amount based on the total amount of the lubricating oil composition 0.005% by mass or more, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and from the viewpoint of preventing corrosion or corrosion wear of lead-containing metals, preferably 0.3% by mass or less. More preferably, it is 0.2 mass% or less, More preferably, it is 0.1 mass% or less, Most preferably, it is 0.08 mass% or less.

  In addition, in the lubricating oil composition of the present invention, when the component (a) is contained, it is preferable not to contain the component (c) from the viewpoint of preventing corrosion or corrosion wear of lead-containing metals, but the base number maintainability is more improved. From the viewpoint of enhancing the corrosion resistance or corrosion wear prevention performance of the lead-containing metal, it is preferable to contain a specific amount of the component (c). In that case, the mass ratio (MS / M) of the total amount of metal (M) caused by the metal detergent and the metal amount (MS) of the salicylate soap (equivalent metal salt) component in the salicylate detergent is not particularly limited. However, it is preferably 0.5 or less, more preferably 0.4 or less, particularly preferably 0.3 or less, from the viewpoint of corrosion of lead-containing metal or corrosive wear, preferably from the viewpoint of base number maintenance. Is 0.05 or more, more preferably 0.1 or more.

  In addition, in the lubricating oil composition of the present invention, when the component (b) is contained, it is preferable not to contain the component (c) from the viewpoint of preventing corrosion or corrosion wear of the lead-containing metal. From the viewpoint of enhancing the corrosion resistance or corrosion wear prevention performance of the lead-containing metal, it is preferable to contain a specific amount of the component (c). (B) When a salicylate detergent is included as a component and / or (c) when a component is included, the amount of metal (MO) resulting from an overbased component such as calcium carbonate and a salicylate soap in a salicylate detergent ( The mass ratio (MS / MO) of the equivalent metal salt) component to the metal amount (MS) is not particularly limited, but is preferably 0.5 or less, more preferably from the viewpoint of preventing corrosion or corrosion wear of lead-containing metals. Is 0.4 or less, particularly preferably 0.35 or less, and is preferably 0.05 or more, more preferably 0.1 or more, and particularly preferably 0.2, in that the base number retention can be further improved. That's it.

  The lubricating oil composition of the present invention can be made into a composition capable of suppressing corrosion or corrosive wear of lead-containing metals by the above-described configuration, but in order to further improve its performance or according to other purposes Any additive commonly used in lubricating oils can be added. Examples of such additives include ashless dispersants other than the succinimide ashless dispersant, antioxidants, friction modifiers, antiwear agents other than zinc dithiophosphate, viscosity index improvers, corrosion inhibitors, Examples thereof include additives such as rust preventives, demulsifiers, metal deactivators, antifoaming agents, and coloring agents.

  As the ashless dispersant other than the succinimide-based ashless dispersant, any ashless dispersant used in lubricating oils can be used. For example, a linear or branched alkyl group having 40 to 400 carbon atoms. Alternatively, a nitrogen-containing compound having at least one alkenyl group in the molecule or a derivative thereof can be mentioned. Examples of the nitrogen-containing compound herein include benzylamine, polyamine, Mannich base and the like, and derivatives thereof include boron compounds such as boric acid and borate, (thio) phosphoric acid, ( Examples thereof include phosphorus compounds such as thio) phosphate, organic acids, derivatives obtained by reacting hydroxy (poly) oxyalkylene carbonate, and the like. In the present invention, one or two or more arbitrarily selected from these can be blended.

  The alkyl group or alkenyl group has 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms. When the carbon number of the alkyl group or alkenyl group is less than 40, the solubility of the compound in the lubricating base oil decreases. On the other hand, when the carbon number of the alkyl group or alkenyl group exceeds 400, the low temperature of the lubricating oil composition Since fluidity | liquidity deteriorates, it is unpreferable respectively. This alkyl group or alkenyl group may be linear or branched, but specifically, preferred are derived from olefin oligomers such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene. And a branched alkyl group and a branched alkenyl group.

  In the present invention, the content of the ashless dispersant other than the succinimide-based ashless dispersant is not particularly limited, but is usually 0.1 to 20% by mass, preferably 3 to 3% based on the total amount of the composition. 15% by mass.

  The antioxidant in the present invention may be any ashless antioxidant such as a phenolic antioxidant or amine antioxidant or an organic metal antioxidant that is generally used in lubricating oils. It can be used. By adding an antioxidant, the antioxidant property of the lubricating oil composition can be further enhanced, and not only the corrosion or corrosion wear prevention performance of the lead-containing metal of the composition of the present invention is enhanced, but also the base number maintenance property is further enhanced. be able to.

  Examples of phenolic antioxidants include 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 4,4 ′. -Bis (2-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-isopropylidenebis (2,6-di-tert-butylphenol), 2,2′-methylenebis (4-methyl-6) -Nonylphenol), 2,2'-isobutylidenebis (4,6-dimethylphenol), 2,2'-methylenebis (4-methyl) 6-cyclohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, 2, 6-di-tert-α-dimethylamino-p-cresol, 2,6-di-tert-butyl-4 (N, N′-dimethylaminomethylphenol), 4,4′-thiobis (2-methyl-6) -Tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 2,2'-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4- Hydroxy-5-tert-butylbenzyl) sulfide, bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide 2,2′-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tridecyl-3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3-methyl-5-tert-butyl-4-hydroxyphenyl substituted fatty acid esters and the like are preferable examples. Can do. You may use these in mixture of 2 or more types.

  Examples of amine-based antioxidants include phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, and dialkyldiphenylamine. You may use these in mixture of 2 or more types.

  You may mix | blend the said phenolic antioxidant, an amine antioxidant, and organometallic antioxidant in combination.

  When the antioxidant is contained in the lubricating oil composition of the present invention, the content thereof is usually 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass based on the total amount of the lubricating oil composition. % Or less. When the content exceeds 20% by mass, it is not preferable because sufficient performance corresponding to the blending amount cannot be obtained. On the other hand, the content thereof is preferably 0.1% by mass or more based on the total amount of the lubricating oil composition in that the corrosion or corrosion wear prevention performance of the lead-containing metal material can be maintained for a longer period of time. Preferably it is 1 mass% or more, Most preferably, it is 1.5 mass% or more.

  As the friction modifier, any compound usually used as a friction modifier for lubricating oils can be used. For example, sulfurized molybdenum dithiocarbamate or sulfurized oxymolybdenum dithiocarbamate, sulfurized molybdenum dithiophosphate or sulfurized oxymolybdenum dithiophosphate Molybdenum amine complexes, molybdenum-succinimide complexes, molybdenum friction modifiers such as molybdenum disulfide, alkyl groups or alkenyl groups having 6 to 30 carbon atoms, particularly linear alkyl groups or linear alkenyl groups having 6 to 30 carbon atoms Ashless friction modifiers such as amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, etc., usually in the range of 0.1 to 5% by mass. It can be contained. Especially in the case of sulfur-containing molybdenum compounds such as sulfurized or sulfurized oxymolybdenum dithiocarbamate that increases the sulfated ash content and sulfur content, and sulfurized or sulfurized oxymolybdenum dithiophosphate that further increases the phosphorus content However, if necessary, the amount of molybdenum is 0.1% by mass or less, preferably 0.03% by mass or less, more preferably 0.02% by mass or less, and particularly preferably 0.01% by mass or less.

  As the anti-wear agent other than zinc dithiophosphate, any anti-wear agent generally used in lubricating oil, such as phosphorus-containing anti-wear agent other than zinc dithiophosphate, sulfur-containing anti-wear agent or boron-containing anti-wear agent, is used. Can be used without restriction.

  The phosphorus-containing antiwear agent is not particularly limited as long as it is an antiwear agent containing phosphorus in the molecule.

  The phosphorus-containing antiwear agent in the present invention includes a phosphorus compound represented by the general formula (10), a phosphorus compound represented by the general formula (11), a metal salt thereof, an amine salt thereof or a derivative thereof. It is preferably at least one compound selected from the group consisting of

（一般式（１０）において、Ｘ^１、Ｘ^２及びＸ^３は、それぞれ個別に酸素原子又は硫黄原子を示し、Ｒ^１８、Ｒ^１９及びＲ^２０は、それぞれ個別に水素原子又は炭素数１〜３０の炭化水素基を示す。）

(In General formula (10), X < ¹ >, X < ² > and X < ³ > show an oxygen atom or a sulfur atom each independently, R < ¹⁸ >, R <^19> and R < ²⁰ > are respectively independently a hydrogen atom or C1-C30. Represents a hydrocarbon group.)

（一般式（１１）において、Ｘ^４、Ｘ^５、Ｘ^６及びＸ^７は、それぞれ個別に酸素原子又は硫黄原子（Ｘ^４、Ｘ^５及びＸ^６の１つ又は２つが単結合又は（ポリ）オキシアルキレン基でもよい。）を示し、Ｒ^２１、Ｒ^２２及びＲ^２３は、それぞれ個別に水素原子又は炭素数１〜３０の炭化水素基を示す。）

(In the general formula (11), X ⁴ , X ⁵ , X ⁶ and X ⁷ are each independently an oxygen atom or a sulfur atom (one or two of X ⁴ , X ⁵ and X ⁶ are single bonds or (poly) An oxyalkylene group may be used), and R ²¹ , R ²² and R ²³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

Specific examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ^{18 to} R ²³ include an alkyl group, a cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkyl group, an aryl group, and an alkyl-substituted aryl group. And arylalkyl groups.

  Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like. And alkyl groups such as a group, hexadecyl group, heptadecyl group, and octadecyl group (these alkyl groups may be linear or branched).

  As said cycloalkyl group, C5-C7 cycloalkyl groups, such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, can be mentioned, for example. Examples of the alkylcycloalkyl group include a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylethylcyclohexyl group, a diethylcyclohexyl group, a methylcycloheptyl group, Examples thereof include alkyl cycloalkyl groups having 6 to 11 carbon atoms such as dimethylcycloheptyl group, methylethylcycloheptyl group, and diethylcycloheptyl group (the substitution position of the alkyl group to the cycloalkyl group is also arbitrary).

  Examples of the alkenyl group include butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, An alkenyl group such as an octadecenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is also optional).

  As said aryl group, aryl groups, such as a phenyl group and a naphthyl group, can be mentioned, for example. Examples of the alkylaryl group include tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, and decylphenyl. Group, an alkylaryl group having 7 to 18 carbon atoms such as undecylphenyl group and dodecylphenyl group (the alkyl group may be linear or branched, and the substitution position on the aryl group is also arbitrary). be able to.

  Examples of the arylalkyl group include arylalkyl groups having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, and phenylhexyl group. It may be branched.).

The ^R 18 hydrocarbon group having 1 to 30 carbon atoms represented by the ^{to R 23,} preferably an alkyl group or an aryl group having 6 to 24 carbon atoms having 1 to 30 carbon atoms, more preferably 3 carbon atoms -18, more preferably an alkyl group having 4 to 12 carbon atoms.

As a phosphorus compound represented by General formula (10), the following phosphorus compounds can be mentioned, for example.
Phosphorous acid, monothiophosphorous acid, dithiophosphorous acid, trithiophosphorous acid; phosphorous acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, monothiophosphorous acid monoester, dithiophosphorous acid Monoester, trithiophosphite monoester; Phosphite diester, monothiophosphite diester, dithiophosphite diester, trithiophosphite diester having two hydrocarbon groups having 1 to 30 carbon atoms; Phosphorous acid triesters, monothiophosphite triesters, dithiophosphite triesters, trithiophosphite triesters having three 1-30 hydrocarbon groups; and mixtures thereof.

In the present invention, X ^{1 to} X ³ in the general formula (10) are excellent in preventing corrosion or corrosion wear of copper and further improving long drain performance such as high temperature cleanability, oxidation stability, and base number maintenance. It is preferable that two or more are oxygen atoms, and it is particularly preferable that all of them are oxygen atoms.

As a phosphorus compound represented by General formula (11), the following phosphorus compounds can be mentioned, for example.
Phosphoric acid, monothiophosphoric acid, dithiophosphoric acid, trithiophosphoric acid, tetrathiophosphoric acid; phosphoric acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, monothiophosphoric acid monoester, dithiophosphoric acid monoester, trithiophosphoric acid monoester, Tetrathiophosphoric acid monoester; phosphoric acid diester having two hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphoric acid diester, dithiophosphoric acid diester, trithiophosphoric acid diester, tetrathiophosphoric acid diester; hydrocarbon having 1 to 30 carbon atoms Phosphoric acid triester having 3 groups, monothiophosphoric acid triester, dithiophosphoric acid triester, trithiophosphoric acid triester, tetrathiophosphoric acid triester; phosphonic acid having 1 to 3 hydrocarbon groups having 1 to 30 carbon atoms, Phosphonic acid monoesters, The phosphorus compounds having 1 to 4 carbon atoms (poly) oxyalkylene group; Suhon diester dithiophosphorylated carboxylic acid derivatives of the phosphorus compounds such as propionic acid; and mixtures thereof.

In the present invention, X ^{4 to} X ⁷ in the general formula (11) are excellent in preventing corrosion or corrosion wear of copper and further improving long drain performance such as high-temperature cleanability, oxidation stability, and base number maintenance. 2 or more are preferably oxygen atoms, more preferably 3 or more are oxygen atoms, and particularly preferably all of them are oxygen atoms. One or two of X ⁴ , X ⁵ and X ⁶ may be a single bond or a (poly) oxyalkylene group.

  As a salt of the phosphorus compound represented by the general formula (10) or (11), the phosphorus compound may be a metal base such as a metal oxide, a metal hydroxide, a metal carbonate, or a metal chloride, ammonia, 1 to 1 carbon atoms. Examples thereof include salts obtained by allowing a nitrogen compound such as an amine compound having only 30 hydrocarbon groups or hydroxyl group-containing hydrocarbon groups in the molecule to act to neutralize part or all of the remaining acidic hydrogen.

  Specific examples of the metal in the metal base include alkali metals such as lithium, sodium, potassium and cesium, alkaline earth metals such as calcium, magnesium and barium, zinc, copper, iron, lead, nickel, silver and manganese. And heavy metals such as molybdenum. Among these, alkaline earth metals such as calcium and magnesium and zinc are preferable.

  The structure of the metal salt of the phosphorus compound differs depending on the valence of the metal and the number of OH groups or SH groups of the phosphorus compound. Therefore, the structure is not limited at all. For example, 1 mol of zinc oxide and phosphoric acid diester When 2 moles (one OH group) are reacted, a compound having a structure represented by the following general formula (12) is considered to be obtained as a main component, but it is also considered that polymerized molecules exist. .

  For example, when 1 mol of zinc oxide and 1 mol of phosphoric acid monoester (having two OH groups) are reacted, a compound having a structure represented by the following general formula (13) is considered to be obtained as a main component. However, it is thought that polymerized molecules exist.

  Specific examples of the nitrogen compound include ammonia, monoamine, diamine, and polyamine. More specifically, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine , Hexadecylamine, heptadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine Decylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, methyl ethyl Alkylamines having an alkyl group having 1 to 30 carbon atoms such as amine, methylpropylamine, methylbutylamine, ethylpropylamine, ethylbutylamine, and propylbutylamine (these alkyl groups may be linear or branched). An alkenylamine having a C2-C30 alkenyl group such as ethenylamine, propenylamine, butenylamine, octenylamine, and oleylamine (these alkenyl groups may be linear or branched); methanolamine, ethanolamine, Propanolamine, butanolamine, pentanolamine, hexanolamine, heptanolamine, octanolamine, nonanolamine, methanol ethanolamine, methanol propanolamine, methanol butanol Alkanol amines having 1 to 30 carbon atoms such as amine, ethanolpropanolamine, ethanolbutanolamine, and propanolbutanolamine (these alkanol groups may be linear or branched); methylenediamine, ethylenediamine Alkylene diamine having 1 to 30 carbon atoms such as propylene diamine and butylene diamine; polyamines such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine; undecyl diethyl amine, undecyl diethanol amine, dodecyl di Monoamines and diamines such as propanolamine, oleyldiethanolamine, oleylpropylenediamine, and stearyltetraethylenepentamine Examples thereof include compounds having an alkyl group or alkenyl group having 8 to 20 carbon atoms in polyamine and heterocyclic compounds such as N-hydroxyethyloleylimidazoline; alkylene oxide adducts of these compounds; and mixtures thereof.

  Among these nitrogen compounds, aliphatic amines having an alkyl or alkenyl group having 10 to 20 carbon atoms such as decylamine, dodecylamine, dimethyldodecylamine, tridecylamine, heptadecylamine, octadecylamine, oleylamine and stearylamine (these are It may be linear or branched)).

Examples of the phosphorus-containing antiwear agent include metal salts of phosphorus compounds in which X ¹ , X ² and X ³ in the general formula (10) are all oxygen atoms, and X ⁴ , X ⁵ , X ⁶ and X in the general formula (11). ⁷ is at least one selected from the group consisting of metal salts of phosphorus compounds in which all ⁷ are oxygen atoms (one or two of X ⁴ , X ⁵ and X ⁶ may be a single bond or a (poly) oxyalkylene group). A compound is preferred in that it is excellent in oxidation stability, long drain properties such as high temperature cleanliness, low friction properties and the like.

Further, the phosphorus-containing antiwear agent is such that all of X ⁴ , X ⁵ , X ⁶ and X ^{7 in} the general formula (11) are oxygen atoms (one or two of X ⁴ , X ⁵ and X ⁶ are single bonds or ( A poly) oxyalkylene group.), And R ²¹ , R ²² and R ²³ are each a phosphorus compound which is a hydrocarbon group having 1 to 30 carbon atoms, oxidation stability, high temperature cleanliness, etc. It is preferable in that it has excellent long draining properties, and further enables low friction and further ashing.

  Among these components, a salt of a phosphite diester having two alkyl groups or aryl groups having 3 to 18 carbon atoms and zinc or calcium, an alkyl group or aryl group having 3 to 18 carbon atoms, preferably carbon number Phosphorous acid triesters having 3 alkyl groups of 6 to 12; monoesters of phosphoric acid having one alkyl group or aryl group having 3 to 18 carbon atoms and zinc or calcium; 3 to 18 carbon atoms Salt of diester of phosphoric acid having two alkyl groups or aryl groups and zinc or calcium, salt of phosphonic acid monoester having two alkyl groups or aryl groups having 1 to 18 carbon atoms, zinc or calcium, carbon number Phosphoric acid triester having 3 to 18 alkyl groups or aryl groups, preferably 3 to 12 carbon atoms, alkyl having 1 to 18 carbon atoms Or it is preferably an aryl group is a 3 having a phosphonic acid diester. These components can be arbitrarily blended in one kind or two or more kinds.

  The content of the phosphorus-containing antiwear agent in the lubricating oil composition of the present invention is not particularly limited, but is 0.005% by mass or more, preferably 0.01% by mass in terms of phosphorus element based on the total amount of the composition. %, Particularly preferably 0.02% by mass or more, while the content thereof is preferably 0.1% by mass or less, more preferably 0.08% by mass or less, particularly preferably 0.05% by mass or less. It is. When the content of the phosphorus-containing antiwear agent is less than 0.005% by mass as the phosphorus element, there is no effect on the antiwear property, which is not preferable. On the other hand, the content is 0.1% by mass as the phosphorus element. In the case of exceeding 1, it is not preferable because there is a concern about an adverse effect on the exhaust gas aftertreatment device.

  Examples of the sulfur-containing antiwear agent include sulfur-containing compounds such as disulfides, sulfurized olefins, sulfurized fats and oils, dithiocarbamate, and zinc dithiocarbamate. These sulfur-containing compounds can be contained in the composition of the present invention in the range of 0.005 to 5% by mass as long as the total sulfur content of the composition is not more than the specified amount of the present invention. The content of these is 0.15% by mass or less, preferably 0.1% by mass or less, particularly 0.05% by mass or less, or does not contain these, reducing sulfur and A lubricating oil composition having a long drain property can be obtained.

  As the viscosity index improver, specifically, a so-called non-dispersed viscosity index improver such as a polymer or copolymer of one or more monomers selected from various methacrylates or a hydrogenated product thereof, Or a so-called dispersion-type viscosity index improver obtained by copolymerizing various methacrylic esters containing a nitrogen compound, a non-dispersion type or a dispersion type ethylene-α-olefin copolymer (propylene, 1-butene, 1 -Pentene, etc.)) or a hydride thereof, polyisobutylene or a hydrogenated product thereof, a hydride of a styrene-diene copolymer, a styrene-maleic anhydride copolymer, and a polyalkylstyrene.

  The molecular weight of these viscosity index improvers needs to be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is usually 5,000 to 1,000,000, preferably 100,000 to 900,000 in the case of dispersed and non-dispersed polymethacrylates, for example. In the case of polyisobutylene or a hydride thereof, usually 800 to 5,000, preferably 1,000 to 4,000, and in the case of an ethylene-α-olefin copolymer or a hydride thereof, usually 800 to 500. 3,000, preferably 3,000 to 200,000 are used.

  Further, among these viscosity index improvers, when an ethylene-α-olefin copolymer or a hydride thereof is used, a lubricating oil composition particularly excellent in shear stability can be obtained. One or two or more compounds arbitrarily selected from the above viscosity index improvers can be contained in any amount. The content of the viscosity index improver is usually 0.1 to 20% by mass based on the lubricating oil composition.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds.

  Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Examples include dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.

  Examples of the antifoaming agent include silicone, fluorosilicol, and fluoroalkyl ether.

  When these additives are contained in the lubricating oil composition of the present invention, the content is based on the total amount of the lubricating oil composition, and 0.005 to 5% by mass for each of the corrosion inhibitor, rust inhibitor, and demulsifier. The metal deactivator is usually selected in the range of 0.005 to 1% by mass, and the antifoaming agent is usually selected in the range of 0.0005 to 1% by mass.

  In addition, the lubricating oil composition of the present invention can corrode or corrode the lead-containing metal material by optimizing the ashless dispersant even if the zinc dithiophosphate content is 0.08% by mass or less as the phosphorus content. And a low sulfur lubricating oil composition having a total sulfur content of 0.3% by mass or less. By selecting a lubricating base oil and various additives, the total sulfur of the composition It is also possible to obtain a lubricating oil composition having a content of 0.2% by mass or less, more preferably 0.1% by mass or less, particularly 0.05% by mass or less or 0.01% by mass or less, and substantially no sulfur. Is possible.

  In addition, the lubricating oil composition of the present invention can have a sulfated ash content of 1.0% by mass or less by adjusting the content of metal-based detergents or other metal-containing additives. Yes, it may be 0.8% by mass, more preferably 0.6% by mass or less, and particularly 0.5% by mass or less.

  The lubricating oil composition of the present invention has low sulfur and is excellent not only in corrosion or corrosion wear prevention of lead-containing metal materials, but also in low friction properties, long drain properties (oxidation stability, base number maintenance properties, etc.) and Excellent high-temperature cleanliness, can be preferably used as a lubricating oil for internal combustion engines, and is suitable for an internal combustion engine equipped with an exhaust gas aftertreatment device by using a low-sulfur, low-phosphorus, and low-ash lubricating oil. It is. Also, low sulfur fuel, for example, sulfur content of 50 ppm by mass or less, more preferably 30 ppm by mass or less, particularly preferably 10 ppm by mass or less or substantially free of fuel (eg gasoline, light oil, kerosene, alcohol, dimethyl ether, It is suitable as a lubricating oil for internal combustion engines using LPG, natural gas, etc.). In particular, it can be particularly preferably used as a diesel engine or gas engine lubricating oil having a lead-containing sliding material. Among these, it can be particularly preferably used as a lubricating oil for gas engines.

  The lubricating oil composition in contact with the lead-containing metal material of the present invention is a lubricating oil for drive systems such as automatic or manual transmissions, grease, wet brake oil, hydraulic hydraulic oil, turbine oil, compressor oil, bearing oil, It can also be suitably used as a lubricating oil such as refrigerator oil.

  The contents of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Examples 1-3, Comparative Examples 1-3)
As shown in Table 1, lubricating oil compositions of the present invention (Examples 1 to 3) and comparative lubricating oil compositions (Comparative Examples 1 to 3) were prepared.

The following evaluation tests were performed on the obtained compositions.
(Change in elution amount of lead by NOx absorption test over time)
The amount of lead elution when NOx gas is blown into a test oil containing lead pieces under the conditions (140 ° C or 150 ° C, NOx: 1185 ppm) in accordance with 1992, 10, 465, Japan Tribology Conference Proceedings. The change with time was measured. It shows that lead corrosion can be suppressed, so that there is little lead elution amount. It should be noted that the forced deterioration by the NOx absorption test makes it possible to confirm in a short time the influence of deterioration products on the lead corrosion due to the deterioration of the lubricating oil, particularly the deterioration of the lubricating oil for internal combustion engines.

(Comparative Examples 1-3)
The composition of Comparative Example 1 in Table 1 contains calcium salicylate having a zinc dialkyl phosphate of 0.04% by mass and a soap ratio of 0.76, and a bistype other than the component (A) as an ashless dispersant. The leaching amount of lead at 150 ° C. is as large as 230 ppm by mass and 400 ppm by mass after 47 hours, respectively. Similarly, the composition of Comparative Example 2 contains the component (A), but includes a succinimide-based ashless dispersant other than the component (A), and these quantitative relationships do not satisfy the provisions of the present application. Although there is a large amount of lead elution after 47 hours. The composition of Comparative Example 3 contains a monotype succinimide, but the amount of lead elution is large. From this result, it can be seen that when a large amount of monotype succinimide is contained, rapid lead corrosion may occur after a certain period of time.

(Examples 1-3)
The compositions of Examples 1 to 3 in Table 1 are compositions containing a bis-type succinimide-based ashless dispersant as defined in this application as a main component, and the lead elution amount is suppressed. In particular, it can be seen that the composition (Example 3) containing a bis-type succinimide ashless dispersant having a weight average molecular weight of 6100 and a B / N ratio of 0.33 can remarkably suppress lead corrosion.

Claims (8)

The lubricant base oil contains 0.08% by mass or less of zinc dithiophosphate as phosphorus, or 0.01 to 0.4% by mass of succinimide-based ashless dispersant as nitrogen, lead-containing metal A lubricating oil composition in contact with a material, wherein the succinimide-based ashless dispersant is (A) a nitrogen ratio (mass ratio) of a boron compound derivative of a bis-type succinimide having a weight average molecular weight of 5000 or more. 0.5 or more, and further contains a salicylate detergent,
Lubricating oil composition whose content of said (A) component is 0.01 mass% or more as boron amount on the composition whole quantity basis .   The lubricating oil composition according to claim 1, wherein the molecular weight of the component (A) is 5500 or more and 6500 or less.   The lubricating oil composition according to claim 1 or 2, wherein a B / N ratio of the component (A) is 0.1 or more and 0.4 or less.   The lubricating oil composition according to any one of claims 1 to 3, wherein a soap ratio of the salicylate detergent is 0.6 or more and 0.85 or less. The lubricating oil composition contains one or more selected from phosphorus additives other than zinc dithiophosphate, ashless antioxidants, corrosion inhibitors, and viscosity index improvers. The lubricating oil composition according to any one of items 1 to 4 . The lubricating oil composition according to any one of claims 1 to 5 , wherein the lead-containing metal material contains 1 to 100 mass% of lead. The lubricating oil composition according to any one of claims 1 to 6 , wherein the lubricating oil composition is used for a diesel engine or a gas engine. Lubricating oil composition containing 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount and 0.01 to 0.4% by mass of a succinimide ashless dispersant as a nitrogen amount in a lubricating base oil A method for preventing corrosion or corrosive wear of lead-containing metal materials in contact with a succinimide-based ashless dispersant, wherein (A) a boron compound derivative of bis-type succinimide having a weight average molecular weight of 5000 or more is used . Use a succinimide-based ashless dispersant in which the nitrogen ratio (mass ratio) is 0.5 or more and the content of the component (A) is 0.01% by mass or more as the boron content based on the total amount of the composition. And, further, a salicylate detergent is contained,
A method for preventing corrosion or corrosive wear of lead-containing metal materials.